In general, for each of arbitrary articles and objects, there is widely used a so-called RF tag which incorporates an IC chip to store predetermined information concerning the articles and objects in a readable and writable manner. The RF tag is also called an RFID (radio frequency identification) tag, an IC tag, a contactless tag or the like, and is a micromini communication terminal provided by forming, into a tag (a label) shape, a so-called inlay (an inlet) which has an electronic circuit including an IC chip and a wireless antennal sealed by or coated with a base material such as a resin film. Thus, the communication terminal is configured to wirelessly enable a read-only operation, a write-once operation and a read/write operation of predetermined information from/to the IC chip in the tag by using a reader/writer.
Afterward, the RF tag including the predetermined information is attached to each of the arbitrary articles and objects, the information recorded in the RF tag is picked up by the reader/writer, and then the information recorded in the tag can be recognized, output, displayed and updated as the predetermined information concerning each of the attached articles and the like.
Such an RF tag enables recording data of hundreds of bits to kilos of bits in a memory of the IC chip, and thus a sufficient information amount of the information can be recorded as the information concerning each of the articles and the like. In addition, since communication can be performed In a contactless manner on the reader/writer side, there are not worries about abrasion of a contact, scratches, contamination and the like, and moreover, since a power supply to the tag itself is unnecessary, the tag can be processed, miniaturized and thinned in conformity to a shape and size of the objects to be used.
When such an RF tag is used, there can be recorded various pieces of information concerning each of the articles to which the tag is attached, e.g., a name, an identification symbol, contents, components, an administrator, a user, or a use state and a use situation of the article. Thus, the various pieces of information of such a great amount as to be impossible by characters and a barcode printed and displayed on a label surface can be correctly read or written by only attaching the miniaturized/thinned tag to each of the articles.
Furthermore, in such an RF tag, when an auxiliary antenna is further laminated on a general-purpose inlay constituting the tag, a wireless communication distance of the general-purpose inlay can be increased, or wireless communication can be performed in an arbitrary frequency band, if desired.
Here, in a case where the auxiliary antenna formed of a metal thin film or the like is laminated on the general purpose inlay having an IC chip and an antenna coated only with a film, the above inlay in this state easily receives influences of impact, moisture, a change in temperature and the like, so that a failure, a malfunction, fracture and the like will be caused.
As a cope with the defect, if the auxiliary antenna is laminated on the general-purpose inlay in such a manner, the laminated inlay and the auxiliary antenna are covered with a predetermined cover, or housed in a housing, whereby the inlay and the auxiliary antenna can be protected from the external environment.
For example, in Patent Literature 1, the present applicant suggests a technology which can protect a general-purpose inlay and an auxiliary antenna from the surrounding environment and maintain/improve weather resistance or heat resistance/waterproof properties of an RF tag by laminating the auxiliary antenna on the general-purpose antenna and housing/sealing them in a resin housing in this state.